1. Technical Field
The present invention relates to data processing systems, and more particularly to an electronic processing device that has multiple input/output pins for communicating with the device. Still more specifically, the present invention relates to a method, apparatus, and product for monitoring and controlling an electronic processing device using only a single existing pin of the device.
2. Description of Related Art
A microprocessor or microcontroller is an electronic processing device that includes multiple input/output pins for communicating with the device. These pins are used to input and output data to and from the device.
After applications are developed and embedded in microcontrollers, they frequently do not include any means to monitor their behavior and internal status. This is largely due to the scarcity of resources in the microcontroller's package which provides the input/output pins for the microcontroller. A two-pin serial port could be used for this, but there are drawbacks to this approach. Using a serial port would require the dedication of two of the input/output communication pins of the device, the hardware that drives the port may not be available, and a external test device that has serial port capabilities would be required in order to monitor the microcontroller.
Therefore, a need exists for a method, apparatus, and product for monitoring and controlling a device using only a single existing pin of the device.